Network Address Translation (NAT) box

NAT boxes could solve the pending address shortage in IP networks.

They act as a buffer between the global Internet and IP local networks
(subnet). The local side addresses would have to be unique only at
the subnet level. When a host on the subnet side of a NAT box sends
traffic over the Internet, the NAT box strips out the local address
and replaces it with the globally unique address assigned to that subnet.

If NAT boxes work,

one of the chief reasons for the IP address shortage would disappear
and they could remove the main reason to migrate to IPng.

To date, no one has demonstrated a NAT box that can solve this technical
challenge.